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| Accurate delivery of radiotherapy is vital, not only to ensure destruction of the tumour(s) but to preserve surrounding tissue as much as possible. This requires the patient to lie absolutely still during treatment, which is why many children receive a short acting general anaesthetic during each session. This will apply to all infants, most children under the age of five, and some school age children. Sedation may be less distressing for the child. |
| "Do not go where the path may lead, go instead where there is no path - and leave a trail." ~ Ralph Waldo Emerson ~ |
| Some Common Radiotherapy Questions Answered |
| ORPHANS OF THE CANCER STORM |
| Disclaimer This information page has been prepared by an individual who does not have medical training. However its contents have been reviewed by appropriately qualified medical professionals for accuracy and quality. This page is intended for information purposes only and should not be used as a guide to diagnosis or treatment. If this information raises any concerns about your child’s condition or care protocol, discuss them with his or her paediatrician, oncologist, or other appropriate medical professional who has knowledge of the case. |
| It is often difficult to differentiate the side effects of radiotherapy from those of concurrent chemotherapy, and sometimes the disease itself. It is important that you discuss the possible side effects with your child's radiation oncologist, and be sure you understand what is involved. In retinoblastoma and optic glioma treatment, potential side effects can be divided into short- medium- and long-term. Short term effects may include: loss of appetite: may be perpetuated by unpleasant taste changes. Rinsing with good mouth wash or sucking clear boiled fruit sweets (candy) may help combat these changes. Nausea and vomiting: specific drugs, such as metaclopromide, are available to reduce these symptoms. Fatigue: Energy levels are likely to be higher in the morning. Make sure your child gets enough rest - regular, short naps throughout the day may be more effective. Balance diet, lower streess around you child, and encourage low energy activities which s/he will enjoy. When you go out, don't be afraid to take a pushchair (stroller) with you, even if your toddler is a good walker. This will reduce the potential stress for both of you in the event s/he begins to tire. Hair loss: will only occur in the field of treatment. This may include eye brows and lashes in orbital exposure. During treatment, and for several months after, use a mild, baby shampoo and do not use hairdryers wherever possible. Medicated scalp creams such as aquaphor, are also available. Sunburn like reddening of the skin: limited to the treatment field. Use aloe vera or camomile lotion to soothe the skin. During exposure to the sun, make sure your child's head and eyes are protected (broad rimmed sunhat and sun glasses), and apply good sun cream (spf 15 or above) during treatment and for 6months after. Medium term effects may include: somnolence syndrome: a normal reaction to cranial radiotherapy which occurs up to three months after treatment has ended. This can be alarming for the parent who has not been pre-warned. It is characterised by prolonged drowsiness and deep sleep (up to 24hrs at a time is not uncommon), difficulty speaking, and the symptoms of flu: a low grade fever, nausea and vomiting, headache and irritability. radiation retinopathy: this may occur after high doses of radiotherapy (above 5000cGy) to the orbit, resulting in damage or loss of vision. Long term effects are more difficult to define. The following have been divided into orbital and neurological effects. Orbital Effects Cataracts: Orbital exposure may result in the development of a cataract several years after treatment. The higher the dose of radiotherapy, and the younger the child is at treatment, the earlier and more severe the cataract will develop. However, cataracts are now easily treatable with fairly minor surgery. Hypoplasia: reduced orbital bone growth, may occur in the treatment field. This is usually only true for children who receive radiotherapy as infants, when orbital bone structures are still developing. Typically, growth of the temporal bone (on the side of the eye nearest the ear), and the bridge of the nose are suppressed, and they socket may retract. Soft tissue growth may also be reduced. In some cases, reconstructive surgery may be possible, but this is often a painful process, and may have implications for remaining vision. Stunted growth of tooth roots has also been observed. This may be true for both milk (baby) teeth and adult teeth. Telangiectasia: haemorrhaging of the small blood vessels of the eye. This usually occurs one-two years after treatment in children who have received doses greater than 3000cGy. Secondary dry eye: this may be caused by decreased tear production or by scarring which prevents the eye lids from closing fully. This can be treated by the regular application of artificial tears and other lubricating eye drops. Photophobia: sensitivity to light may be moderate or severe. Use of tinted lens glasses, window blinds and strategic lighting can lessen the effect. Scarring and ulcers on the cornea: may occur when the dose received is greater than 4000 cGy. Glaucoma: increased pressure within the eye may occur many years after radiotherapy. Second cancers: may occur within and outside the field of radiation. These are primarily bone and soft tissue sarcomas. There is more risk for children with the hereditary form of Rb, but research suggests that children are most at risk when irradiated before one year of age. Neurological Effects The following may be an effect of cranial radiotherapy with doses as low as 1800 cGy. In general, the higher the dose, and the younger the age of the child at treatment, the greater the effects are likely to be. The type of neurological impact will depend on the radiotherapy site and the surrounding regions of the brain. The following effects may alter the child's personal learning techniques and/or social behaviour, and it is important for carers, medical professionals and teachers to remain vigilant in order to advocate positive early intervention where it is needed. Cognitive skills Remember that it is very difficult for doctors to predict the type and extent of any cognitive deficiencies resulting from radiotherapy. In general, pre-school age children, particularly those under 24months, are at greatest risk. Learning difficulties: are usually apparent to the child's carer and/or teachers within three-five years of treatment. Issues have been observed particularly with regard to mathematics and problem solving, spatial relationships, attention span, concentration and memory skills. Slower processing speeds: may impair a survivor's ability to make judgements, as slower thought processes will restrict the amount of information available in a given time frame. The challenge of cognitive deficit is often exacerbated by a child's frustration at their inability to keep up with peers in the classroom, and this may foster a belief that they are of lower intellect and therefore less likely to succeed. It is important to remember that many children who exhibit these effects are very bright, and specific educational support may greatly improve their ability to achieve full potential. Seizures Seizures occur in many forms, from a slight loss of awareness (often mistaken as daydreaming), to severe events which may involve loss of consciousness and convulsions. Seizures may affect the entire brain, or a specific area. Scarring of the brain from cranial radiotherapy may cause seizures to develop, even many years after treatment has ended. Many treatments are now available which can successfully control seizures. Hormone dysfunction Radiotherapy for optic nerve glioma may cause permanent damage to the hypothalamus and pituitary gland. These two neurological structures are tightly connected, as the hypothalamus produces substances which control the release of hormones from the pituitary gland. Implications of damage to these structures may be dramatic as they are responsible for the overall function of the endocrine system. Damage to this system may result in: slow or stunted growth: growth hormone injections may be given to aid continuing growth following cranial radiotherapy. precocious puberty (8 for girls, 10 for boys): which may result in short stature as bones cease to grow when the body reaches sexual maturation. It is important that your child be monitored by an endocrinologist if it is suspected that radiotherapy may interfere with the hypothalamic/pituitary region of the brain. All of the above are potential side effects. It is important to remember that radiotherapy is being offered to preserve and improve the life of your child. In spite of these effects, the vast majority of children who receive cranial radiation grow up to lead normal, successful and fulfilled lives. The following two pictures are of the same child, before and after radiation. |
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| When the set up is complete, and everyone is sure of the conscious child's co-operation, you must leave the room with the technician. During treatment, you may be allowed to observe your child on a video monitor and offer comfort via a microphone. In such instances, you must be sure you do not distract the radiotherapist. |
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| If your child needs sedation, this will usually take place in the treatment room. Before each treatment, your child will be placed on the treatment table, and their mask will be bolted down to hold the head still. The machine will then be moved into the pre-planned position, and measurements may be taken to confirm this. You may be allowed to stay with your child throughout this process. |
| Your child's breathing and heart rate will be closely monitored by an anaesthetist, and she may be intubated to manage breathing. This involves inserting a flexible tube into the throat after your child has been anaesthetised, and it will be removed once the procedure is complete. |
| 2) Once the mask is made, a simulation will be undertaken. Typically, this takes several hours and will involve both the radiation oncologist and radiotherapist. Special x-rays and measurements will be taken and used to calculate the treatment field. The machine will be adjusted and it's position recorded for future set-up. Small marks will then be made on the mask to identify treatment areas. |
| There are two preparation steps before treatments can begin. These may take place on the same day, or several days apart. Most hospitals will allow parents to remain with the child throughout the preparation process, though babies and young or distressed children may need sedation during both procedures. 1) Children receiving radiation to the head wear a light, plastic mask during treatments. Making the mask is a simple process which will be done by a trained technician. Your child will be asked to lie down whilst a sheet of water-softened pliable mesh is placed lightly over the face and quickly moulded to individual facial features. The material will be slightly warm and takes only a few minutes to set. It will then be removed and used as a mould for the final plastic shell to be used during treatment. The mask itself will have holes through which radiation will reach the tumours, and a large hole tol allow the child to breathe and be intubated if necessary during treatment (see SEDATION below). |
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| Radiotherapy is given in fractionated doses, usually over a period of 4-8 weeks. The treatment itself takes only two or three minutes. However, preparation for each treatment will involve setting up the equipment and placing the child in the correct position to ensure precise delivery. This may take about half an hour. |
| Radiation is measured in units called centigrays (cGy). Doses vary depending on the individual situation, and you should check the plans with your child's radiation oncologist. For retinoblastoma, the common dose is between 180-200 cGy per day over a period of 4-6 weeks, giving a total dose of 3500-4600 cGy. However, researchers are currently investigating the options of using lower doses in combination with other treatments such as chemotherapy. |
| Radiotherapy is employed for solid tumours (such as retinoblastoma and optic nerve glioma) when the mass is localised and has not metastasised to distant areas of the body. Examples of radiotherapeutic intervention are: When the tumour is large When Rb is multi-focal (more than one tumour in the eye) When the tumour is situated close to the optic nerve or fovea. When seeds (tiny fragments of a tumour) have invaded the vitreous. When the tumour has spread beyond the eye to the socket, optic nerve or brain), or there is a concern that this is likely to happen without treatment. When the child has trilateral retinoblastoma. |
| Proton Beam Radiation has been part of medical research since the early 1950s. However, it has only been since the first patient based centre opened in 1990 that this therapy has become widely used in cancer treatment. The equipment used for PBR is more expensive than that used with EBR, and is still in development. It is therefore only available at a handful of university and medical research centres around the world, each of which may have specific criteria for treatment acceptability. A list of centres can be found at www.orphancancer.org/General/Treatment/protonbeamtherapy.html |
| Standard External Beam Radiation (EBR) uses either cobalt or photon beams which are produced by a machine called a linear accelerator. Proton Beam Radiation (PBR) uses large, positively charged particles which are heavier than normal photons used in EBR. These are generated within a large machine called a cyclotron. During standard EBR, healthy tissues may also be irradiated due to the technical challenges of conforming the beams exclusively to the tumour site. To reduce the potential damage to healthy tissues, less-than-optimal doses are frequently administered. Protons are more precisely delivered as they are more adept at preserving their energy whilst travelling through the body. This means that deep seated tumours may be more successfully treated, and higher doses of radiation can be given to destroy the tumour, while significantly reducing the negative effects to healthy surrounding tissues and organs. The National Association for Proton Therapy website has a more in depth discussion of the differences between EBR and PBR. www.proton-therapy.org/howit.htm |
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| Your child will be free to leave the treatment unit right after treatment if no sedation is used. If she requires sedation during treatment, she will be allowed to leave hospital once she is fully conscious and drinking fluids. Most children cope exceptionally well with daily radiotherapy treatments. |
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